1. Field of the Invention
This invention relates to a microwave waveguide switch and, in particular, to an R-switch that has a transformer located in at least one of the waveguide paths.
2. Description of the Prior Art
It is known to use R-switches in communication satellites. In fact, in most satellites, numerous R-switches are employed. The size of the R-switch is important as there are so many of them used in a spacecraft and weight and volume reductions can result in large cost savings. Also, the size of the R-switch can impose restraints on a transponder layout and a reduction in size and volume of R-switches can provide extra flexibility in the layout process.
Usually, an R-switch has three waveguide paths, a straight central path and two curved E-bend waveguide paths. In a variation of existing R-switches, the two outer paths have waveguide corners instead of curved E-bends. Generally, the waveguide corner R-switch has worse isolation and return loss performance compared to the E-bend R-switch. Also, the straight waveguide in the centre path limits the amount of size reduction that can be achieved. R-switches are generally used in association with an actuator which moves the R-switch to various predetermined positions. Since there are numerous R-switches used in most communication satellites, any mass or volume saving can result in a substantial overall saving.